1. Field of the Invention
The present invention relates to a printing method, a printing system, and a storage medium storing a program.
2. Related Art
Examples of printing apparatuses such as a printer, a plotter, and a facsimile include an ink-jet type that prints an image on a medium (paper, cloth, OHP transparency film and the like) with an ink ejected from a nozzle. This type of printing apparatus alternately performs an ink ejecting operation for intermittently ejecting an ink while a head is moved and a carrying operation for carrying the medium in a direction crossing a movement direction of the head, thus printing the image on the medium.
In recent years, a printing apparatus that can perform “borderless printing” in which an image is printed on a medium without forming a margin has been increasing. This printing apparatus ejects ink to a wider range than the medium, thus achieving borderless printing. Moreover, in this printing apparatus, a convex portion and a concave portion are provided in a supporting member for supporting the medium in order to prevent ink from landing on the supporting member and making a reverse side of the medium dirty. The ink is ejected from the nozzle in such a manner that the ink that does not land on the medium lands on the concave portion (see Japanese Patent Laid-Open Publication No. 2002-103584, for example).
In borderless printing, ink may fall off the medium when printing is performed at an edge portion of the medium. Thus, during printing at the edge portion of the medium, a nozzle opposed to the concave portion is used so as to make the ink that does not land on the medium land on the concave portion. In the case when printing is performed at the edge portion of the medium in that manner, usable nozzles are limited and a number of usable nozzles are reduced. Therefore, a range in which dots can be formed during a dot forming operation is reduced.
On the other hand, when the range in which dots can be formed at the dot forming operation becomes narrower, it is necessary to reduce a carrying amount during the carrying operation. In other words, in the case where printing is performed at the edge portion of the medium, it is necessary to make the carrying amount in the carrying operation smaller, as compared with the case where printing is performed in a portion at a center of the medium.
However, when the carrying operation by the small carrying amount continues needlessly, printing time becomes longer.
Further, in this type of printing apparatus, some perform printing by varying carrying amounts. For example, a printing apparatus is known which performs printing by setting a carrying amount for a trailing edge portion of the medium to be smaller than that for an intermediate portion in order to enlarge a region in which an image is printed (see JP-A-7-242025, for example). In this printing apparatus, a timing of switching of the carrying amount is determined based on a size of the medium for which printing is to be performed. For example, the carrying amount is switched, on the condition that the number of passes from the start of printing (this number corresponds to the number of movements that a head is moved in a movement direction) reaches a defined number.
In this type of printing apparatus, some include a sensor for detecting a medium provided upstream of a head in a medium carrying direction. In this printing apparatus, when a trailing edge of the medium is detected by the sensor, printing is terminated after printing is performed for a predetermined number of passes, and then the medium is discharged. In this printing apparatus, control for the carrying amount does not work with detection of the trailing edge of a medium. Thus, a trouble may occur in the case where a length of the medium on which the printing is to be performed is different from a length of a medium that is specified for control. For example, when the medium on which printing is to be performed is shorter than the medium specified for control regarding the length in the medium carrying direction, the medium is discharged with unprinted portions that are long in the head movement direction left at several positions. Moreover, during borderless printing, when the medium on which printing is to be performed is longer than the medium specified for control, the number of carrying of the medium by a small carrying amount increases as compared with a normal case, and thus makes the printing time longer.